The present invention relates to aerobic decomposition of animal and other organic waste, such as sewage sludge, and more particularly concerns a method and apparatus which utilizes movable process cars which permit the aerobic thermophilical composting of organic waste material within a limited area.
It is known that organic waste material may be efficiently processed by providing an environment which enhances the growth of thermophilic bacteria in the waste product. One such process for aerobically decomposing organic waste material is disclosed in applicant's U.S. Patent 4,139,640. According to the method in this mentioned patent, a quantity of undecomposed organic waste material is introduced into one end of an elongate composting vessel. This quantity of material is maintained in the vessel until the material attains a predetermined thermophilic temperature. This quantity of material is then agitated, intermixed and advanced into a succeeding station in the elongate composting vessel toward the opposite end of the vessel. The quantity of material is then once again maintained in a quiescent state until a succeeding quantity of material deposited at the end of the vessel vacated by the advanced quantity of material reaches a predetermined thermophilic temperature. Each quantity of material is repeatedly and intermittently mixingly advanced to a succeeding station and maintained in a quiescent state until the last deposited quantity reaches a predetermined thermophilic temperature. This process is continued until the quantity of material is ultimately discharged from the composting or containing vessel.
The method described in the above identified patent has proved to be highly effective. It does, however, suffer from limitations of size for some small scale applications. The present invention overcomes not only the disadvantages as to size, which were heretofore believed necessary to successfully carry out the process, but also greatly reduces the cost of process equipment for small scale operations, much of which was necessitated by the large elongate vessel.
It is therefore an object of the present invention to provide a method and apparatus for effecting the aerobic thermophilic bacterial composition of organic waste materials for small scale operations.
It is a further object of the present invention to reduce the space requirements for processing equipment of aerobic thermophilic composting of organic waste material.
It is a further object of the present invention to provide a method and apparatus for economically aerobically thermophilically composting organic waste material.
It is yet another object of the present invention to provide a method and apparatus for aerobically thermophilically composting waste material in which the capacity of the system may be readily expanded or contracted.